By JOE COSCARELLI

May 14, 2015

WHEN the Central Park Mall began hosting musical performances in the 1860s, only classical was permitted. In the 1920s, with the Naumburg Bandshell’s arrival, collars loosened and the sounds of the day — folk, pop, jazz — trickled in. But only in the last three decades, with the rise of SummerStage, the annual festival of largely free shows presented by the City Parks Foundation, has the tradition of live music in the city’s public spaces been truly cemented — and gleefully trampled on.

Christened in 1986 by Sun Ra and his Arkestra, SummerStage, celebrating its 30th season, has expanded to all five boroughs and many more genres, with appearances by punk poets (Patti Smith, Lou Reed), international stars (Celia Cruz) and resourceful folk rockers (the Indigo Girls, during the 2003 blackout). The program has become as reliable a source of summertime sound as Mister Softee trucks, with a selection as varied.